Handling
Milligrams, micrograms and the units that are not weights
A factor of a thousand, a factor that is not a factor at all, and where the decimal point actually goes.
Most of what is sold in this market is sold by weight, and weight is the easy case. The confusion starts where a number on a label is not a weight at all.
The thousand
A milligram is a thousand micrograms. Everything on this shelf is labeled in milligrams, and a good deal of the literature is written in micrograms, which puts a factor of a thousand between the vial and the paper. It is the single most common arithmetic error in this field and it is silent in both directions.
| Written | Means | In milligrams |
|---|---|---|
| 1 mg | one milligram | 1 |
| 1,000 mcg | one thousand micrograms | 1 |
| 250 mcg | two hundred and fifty micrograms | 0.25 |
| 5 mg | five milligrams | 5 |
Units that are not weights
An international unit measures activity rather than mass. It is defined per substance by an agreed biological standard, so a unit of one thing and a unit of another have no fixed relationship to each other and no fixed relationship to milligrams. There is no universal conversion and anyone offering you one is guessing.
Nothing currently on this shelf is sold in international units — every product here is labeled in milligrams, milliliters or strips — but the convention turns up constantly in the surrounding literature, and a number in IU cannot be compared to a number in mg without the specific standard for that substance.
Per milliliter is a third thing
A concentration is not a quantity. A vial holding 10 mg made up to 2 mL is 5 mg/mL; the same vial made up to 1 mL is 10 mg/mL and still 10 mg of peptide. Sprays are the case where this bites, because the label carries a total weight and the useful figure is the amount per actuation.
For laboratory research use only. Not a drug, not a supplement, and nothing here is a claim about what any of this material does in a person or an animal.